<!DOCTYPE html>
<html>
  <head>
    <title>Stretchy mover</title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
    <link rel="stylesheet" href="/fonts/ahem.css" />
    <style>
      @font-face {
        font-family: operators;
        src: url("/fonts/math/operators.woff");
      }
      math {
        font: 25px/1 Ahem;
      }
      mo {
        font-family: operators;
      }
    </style>
  </head>
  <body>
    <math display=block>
     <mrow>
      <mrow>
        <mover>
          <mo stretchy="false">&#x2191;</mo>
          <mn>B</mn>
        </mover>
      </mrow>
     </mrow>
    </math>
  </body>
</html>
